Indicia display device

ABSTRACT

An indicia display device utilizing at least one pair of grids with each grid having a plurality of lines and piezoelectric means for moving said grids one relative to the other to effect the display and disappearance of indicia.

United States Patent Golay Sept. 24, 1974 [54] INDICIA DISPLAY DEVICE 1,521,007 12/1924 Chubb 346/69 3,047,865 7/1962 Schaeder 346/69 Inventor: Mafcel Gmay, 1095 LutrY/Vd, 3,082,560 3/1963 Elvestrom 40/36 ux swltleflafld 3,146,367 8/1964 McNaney 3l0/8.6 x p 17, 3,399,475 Rinder X [2]] Appl 9 244779 Primary Examiner-Harland S. Skogquist Assistant Examiner-John F. Pitrelli [52] US. Cl 40/28 C, 310/86, 340/336 [51] Int. Cl. G09f 11/00 57 ABSTRACT [58] Field of Search 40/130 E, 28 C, 130 K, H

40/132 D, 10653, 133, 10651, 10652, 7; An 1nd1 c1a dlsplay devlce ut1l1z1ng at least one pan of 340/336, 324 310/85 X gr1ds with each gnd having a plurahty of llnes and p1- ezoelectric means for moving said grids one relative to 5 References Cited the other to effect the display and disappearance of UNITED STATES PATENTS 957,120 5/1910 Spiegel 40/137 5 Claims, 5 Drawing Figures c'0/vrZvz WFOPMAflO V r/zf 1 flows? f i P .7 warm? INDICIA DISPLAY DEVICE This invention relates to indicia display devices and more specifically to a novel and improved device for the display of numerals and other indicia in digital display devices that requires relatively little power, is compact, and requires little depth.

Various types of indicia display devices have been proposed, such as glow tubes, wherein electrodes in the form of numerals are disposed in depth in a gaseous atmosphere and other types of devices such as light emitting semiconductors and structures utilizing filaments and grids to energize selective portions of a pattern to effect the display of desired indicia. Such devices require a material depth for installation, some utilize relatively large amounts of power for operation, and some exhibit poor contrast and aging characteristics. This invention overcomes the disadvantages of prior devices and provides a display device that will function instantaneously on relatively little power, occupies a very small space, provides a clear and distinct display of numerals or other indicia and has an indefinite life.

Another object of the invention resides in the provision ofa novel and improved indicia display embodying an electro-optical system for visually displaying selective portions of a pattern for the formation of selected numerals or other indicia.

Still, another object of the invention resides in the provision of a novel and improved indicia display device utilizing piezoelectric devices for displacement of optical elements arranged in a selected pattern to effect the formation of numerals of other indicia.

The objects of the invention are attained through the utilization of a plurality of optical elements producing moire fringes which .are arranged in a predetermined pattern and actuated by piezoelectric elements. With this arrangement, actuation of selected elements will produce a visual display of indicia as for instance the numerals 1 through 9 and 0.

An aspect of this invention comprises the use of ultrasonic vibrations to decrease the sticktion between displaying elements. By sticktion is meant any static friction which would so operate during the displacement of certain elements with respect to each other as to cause said elements to assume relative rest positions which are displaced with respect to the relative rest positions they would have in the absence of said static friction.

The above and other objects and advantages of the invention will become more evident from the following description and'accompanying drawings forming part of this application.

In the Drawings:

FIG. I is a diagrammatic view of indicia displaying means in accordance with the invention.

FIG. 2 is a cross-sectional view of one of the segments of the indicia displaying pattern of FIG. I and taken along the line 2-2 thereof,

FIG. 3 is a cross-sectional view similar to FIG. 2 to illustrate the displacement of one portion of the structure relative to the other in order to cause the disappearance of a line,

FIG. 4 is a rear elevational view of the structure shown in FIG. 2, and

FIG. 5 is an enlarged fragmentary portion of the piezoelectricmeans for displacing the rear element of each segment of the pattern shown in FIG. 1 relative to the front element.

The display system in accordance with the invention provides novel and improved means for displaying indicia such as numerals for use in digital read-out devices and embodies means for producing moire fringes and wherein the optical elements producing such fringes are actuated by piezoelectric elements. With this arrangement, an exceedingly thin structure can be produced so that very little space is required for installation. Moreover, power requirements are relatively small which makes the display device particularly useful for use on portable equipment, though it is apparent that it is equally applicable to all types of equipment requiring a digital read-out.

Referring to FIG. 1 which illustrates diagrammatically a display device in accordance with the invention for displaying a single digit and utilizes a transparent plate 10 together with seven slidable plates 11 through '17, the plates 11 through 17 are arranged in the form of parallelogram with the plate 17 forming a crossbar. As will be described, each of the plates 11 through 17 canbe shifted relative to the plate 10 to cause bars 11' through 17, as the case may be, to appear or disappear as may be desired. With this arrangement, any numeral,

namely, 1 through 9 and 0, can be displayed by the pattern. Displacement of the plates 11 through 17 is effected by an appropriate electronic selector 18 which applies power to the piezoelectric elements utilized for displacement of the plates. Control signals are fed to the selector by appropriate electrical circuitry represented by the conductor 18. A power supply 20 energizes the selector 18 together with an electromechanical vibrator 19 which has its vibrating mechanical element coupled in a suitable manner to the plate 10 and is energized only during changes in indicia display to reduce sticktion between the plates 11 through 17 on one hand and the plate 10 on the other hand, and thereby facilitates displacement of the plates 11 through 17 relative to the plate 10.

FIGS. 2 through 4 illustrate the structural details of the segment 17 in greatly enlarged form to facilitate an understanding of the operation of the display device. The plate 10 is formed on a transparent material, such as glass or the like, and carries on its backside an opaque coating 10' which is illustrated by a heavy black line. A plurality of slits 22 are formed in the coating 10', each of which have a length corresponding to the length of the bar 17 produced by displacement of the plate 17in FIG. 1. While only six slits 22 havebeen illustrated, the actual structure may utilize as many as such slits each of which may typically have a width of 1.90 microns and a center-to-center spacing of approximately 4 microns. The length of each slit may be of the order of 3 mm.

The plate 17 which overlies the slits 22 may be formed of either an opaque or transparent material. This plate carries a plurality of strips of a reflecting material 23 corresponding in length, width and spacing to the slits 22. In the case wherein the plate 17 is formed of an opaque material, or is provided with an opaque coating, when the plate is in the position shown in FIG. 2, the reflective strips 23 on the plate 17 will be precisely aligned with the slits 22 carried by the plate 10 and the light reflected from the strips 23 will make the bar 17' of FIG. 1 visible. Should the plate 17 be of a transparent material, then the backside of the plate should be enclosed in a light-proof compartment.

The plate 17 is secured in position on the plate 10 by two sets of piezoelectric elements generally denoted by the numerals 24 and 25, which elements function to shift the plate 17 relative to the plate 10. The disposition of the elements 24 and 25 is shown more clearly in FIGS 4 and 5. The element 24 consists of two elongated piezoelectric structures 26 and 27 with the upper end of the piezoelectric structure 26 being cemented or otherwise secured to the plate 17 at 28. The lower end of the piezoelectric structure 26 is hinged at 29 to the lower end of the piezoelectric structure 27. The upper end of the piezoelectric structure 27 is cemented to the plate 10 at 30. The element 25 also consists of two piezoelectric structures 31 and 32 with the lower end of the structure 31 secured to the plate 17 at 33 and the upper end hinged at 34 to the upper end of the structure 32. The lower end of the structure 32 is secured at 35 to the plate 10. A fragmentary cross-sectional view of the piezoelectric element 24 is shown in FIG. and the element 25 is constructed in the same manner as the element 24. It will be observed that each of the piezoelectric structures 26 and 27 consists of two piezoelectric elements 36 and 37 having an electrode 38 therebetween and overlying electrodes 39 and 40. Piezoelectric structures such as 26, 27, 31 and 32 are designed as bimorphs and will bend when the voltages applied to the two piezoelectric elements which they comprise cause one of said elements to elongate and the other to contract. Conductors 41 through 43 are connected to the electrodes 38, 39 and 40 of the piezoelectric structure 26 while conductors 44, 45 and 46 are connected to the electrodes 38, 39 and 40 of the piezoelectric structure 27. These conductors are all connected to the selector 18 for the application of voltages to the electrodes in order to effect bending of the piezoelectric elements.

With the plates and 17 being positioned as shown in H0. 2, a bar 17' will not be visible through the plate 10. Upon the application of voltages to the electrodes as described above, the piezoelectric structure 26 will flex convexly to the right while the piezoelectric structure 27 will flex concavely to the right. At the same time, the piezoelectric structure 31 will flex convexly to the right while the structure 32 will flex concavely to the right. This action will cause the plate 17 to shift a distance of one-half of the center-to-center distance of the slits to the right and, thus, cause the bar 17 to disappear. It is of course evident that a reverse operation can also be obtained, namely, that in the presence of an applied voltage the bars 11 through 17 will appear while in the absence ofthe voltage they will disappear.

With the structure as described above wherein all of the plates 11 through 17 are supported by piezoelectric elements as described in connection with FIGS. 2

through 5, the control ofthe voltages applied to the piezoelectric elements of selected plates will cause the associated bar to appear or disappear so that any numeral 1 through 9 and 0 can be readily displayed. During the application and removal of voltages to change a given indicia, the vibrator 19 is actuated to minimize the sticktion between the plates 11 through 17 and the plate 10 and thereby avoid an undesired shift of plates 11 through 17 with respect to their desired positions. While the vibrator may operate at any desired frequency, a frequency of kilocycles for a duration of approximately one millisecond will effectively reduce the sticktion.

While only one embodiment of the invention has been illustrated and described, it is apparent that alterations, modifications and changes may be made without departing from the true scope and spirit thereof as defined by the appended claims.

What is claimed is:

1. An indicia display device comprising twojgrids each having a plurality of fine lines and positioned in overlying relationship and piezoelectric means for displacing said grids one relative to the other to move thee lines of one grid into and out of registry with the lines of the other grid, said piezoelectric means each comprising two piezoelectric structures hinged one to the other in the form ofa V, said piezoelectric means being inverted one relative to the other and each having one free end of one piezoelectric means secured to one grid and the other free end secured to the other grid and electrodes on said structures for applying a potential thereto.

2. An indicia display device according to claim 1 wherein one of said grids comprises a first plate having a plurlaity of fine light transmitting slits and said other grid comprises a second plate having a plurality of light reflecting lines corresponding in size and spacing to said slits.

3. An indicia display device according to claim 2 including a vibrator connected to one of said plates for minimizing the sticktion between said plates during displacement thereof.

4. An indicia display device according to claim 3 including a plurality of pairs of grids with said first plate of each pair of grids forming part of a single plate with said slits of the grids being arranged in a geometric configuration, said second plate of each pair of grids being placed in overlying relationship with said single plate and said vibrator being mechanically coupled to said single plate. v

5. An indicia display device according to claim 1 including a plurality of pairs of grids arranged in a geometric configuration whereby displacement of the grids of selected pairs will effect the display of selected indicldl= 

1. An indicia display device comprising two grids each having a plurality of fine lines and positioned in overlying relationship and piezoelectric means for displacing said grids one relative to the other to move thee lines of one grid into and out of registry with the lines of the other grid, said piezoelectric means each comprising two piezoelectric structures hinged one to the other in the form of a V, said piezoelectric means being inverted one relative to the other and each having one free end of one piezoelectric means secured to one grid and the other free end secured to the other grid and electrodes on said structures for applying a potential thereto.
 2. An indicia display device according to claim 1 wherein one of said grids comprises a first plate having a plurlaity of fine light transmitting slits and said other grid comprises a second plate having a plurality of light reflecting lines corresponding in size and spacing to said slits.
 3. An indicia display device according to claim 2 including a vibrator connected to one of said plates for minimizing the sticktion between said plates during displacement thereof.
 4. An indicia display device according to claim 3 including a plurality of pairs of grids with said first plate of each pair of grids forming part of a single plate with said slits of the grids being arranged in a geometric configuration, said second plate of each pair of grids being placed in overlying relationship with said single plate and said vibrator being mechanically coupled to said single plate.
 5. An indicia display device according to claim 1 including a plurality of pairs of grids arranged in a geometric configuration whereby displacement of the grids of selected pairs will effect the display of selected indicia. 